Junior Captain denoted a military rank within both the Chiss Defense Force and the Chiss Expansionary Defense Fleet of the Chiss Ascendancy. This rank was positioned above Senior Commander but held less authority than mid captain.
Vorlip, who commanded the Chiss Defense Force Transport named Tomra, held the rank of Junior Captain circa 39 BBY. Approximately around 18 BBY, Ovinon, a member of the crew on the Chiss heavy cruiser Grayshrike and the first officer serving on the Chiss frigate Midsummer, both held the rank of Junior Captain. In that same year, Evroes'ky'mormi, whose core name was "Oeskym," was a Junior Captain and functioned as the weapons officer aboard the Nightdragon man-of-war warship named _Vigilant'_s.
Firmus Piett, a human officer, once held the rank of junior captain while in service to the Imperial Navy of the Galactic Empire under the command of Grand Moff Wilhuff Tarkin. Piett eventually progressed through the ranks, achieving the positions of captain, admiral, and ultimately fleet admiral.
The title of Junior Captain was first introduced in flashback sequences within the 2020 novel Thrawn Ascendancy: Chaos Rising, which marked the initial book in Timothy Zahn's Ascendancy Trilogy.